If I'm making a web application which integrates with a server-side backend, would it be considered best practice to use HTTP methods semantically? That is, for example, if I'm fetching data (e.g., to populate a menu, etc.), I would use GET, but to update data (e.g., save a record), I would use POST. (I realise there are other methods that may be even more appropriate, but we need to consider browser support.)

I can see the benefits of this in the sense that it's effectively a RESTful API, but at a slightly increased development cost. In my previous projects, I've POST'd everything: Is it worth switching to a RESTful mindset simply for the sake of best practice?